1. Field of the Invention
The present invention relates to electric-component mounting apparatus and method for moving a suction nozzle holding, by suction, an electric component, and mounting, on a circuit substrate such as a printed circuit board, the electric component held by the suction nozzle, and particularly to the art of handling a defective suction nozzle.
2. Related Art Statement
This sort of electric-component (xe2x80x9cECxe2x80x9d) mounting apparatus is disclosed in, e.g., U.S. patent application Ser. No. 08/977,662 now U.S. Pat. No. 6,161,277 assigned to the assignee of the present application. The disclosed mounting apparatus includes a movable member; a rotatable body which is rotatably supported by the movable member; and a plurality of suction nozzles which are supported by the rotatable body. When the movable member is moved, respective electric components (xe2x80x9cECsxe2x80x9d) held by the suction nozzles are simultaneously transferred, and when the rotatable body is rotated, the suction nozzles are sequentially moved to an EC-mount position where each of the suction nozzles mounts, on a circuit substrate (xe2x80x9cCSxe2x80x9d), the EC held thereby.
The above-identified EC mounting apparatus iteratively holds and transfers ECs and mounts the ECs on CSs. Accordingly, in an EC mounting operation, one or more of the suction nozzles may become defective, for example, may be bent or curved, be stained, or be worn, and may fail to hold or mount an EC. Conventionally, each defective suction nozzle is manually exchanged with a normal suction nozzle by an operator. However, the nozzle exchange is cumbersome and time-consuming. Since the EC mounting operation is suspended by the nozzle exchange, the EC mounting efficiency is lowered.
The present invention provides an electric-component mounting apparatus and an electric-component mounting method which have one or more of the technical features that are described below in respective paragraphs given parenthesized sequential numbers (1) to (25). Any technical feature which includes another technical feature shall do so by referring, at the beginning, to the parenthesized sequential number given to that technical feature. Thus, two or more of the following technical features may be combined, if appropriate. Each technical feature may be accompanied by a supplemental explanation, as needed. However, the following technical features and the combinations thereof are just examples to which the present invention is by no means limited. Rather, the concept of the present invention should be construed based on the entire description of the specification and the drawings.
(1) According to a first feature of the present invention, there is provided an apparatus for moving at least one suction nozzle holding, by suction, an electric component, and mounting, on a circuit substrate, the component held by the nozzle, the apparatus comprising a nozzle-defect detecting device which detects a defect of the suction nozzle; and a nozzle exchanging device which automatically exchanges the defective suction nozzle having the detected defect, with a normal suction nozzle. The present electric-component (xe2x80x9cECxe2x80x9d) mounting apparatus may be one which includes only one suction nozzle, or one which includes a plurality of suction nozzles. The at least one suction nozzle may be moved by a movable member which is movable to an arbitrary position on a plane, or may be rotated by a rotatable body which is rotatable about an axis line. When the nozzle-defect detecting device automatically detects a defect of the suction nozzle, the nozzle exchanging device automatically exchanges the defective suction nozzle having the defect, with a normal suction nozzle. Thus, the present EC mounting apparatus exchanges the suction nozzles more quickly than an operator does with his or her hands. Although the EC mounting operation may be suspended by the nozzle exchange, the decrease of the EC mounting efficiency is minimized. In addition, since the EC mounting apparatus needs no intervention of the operator for performing the nozzle exchange and can full-automatically perform the EC mounting operation, the operator need not do the nozzle exchange and can do another task. Thus, the working efficiency of the operator is increased.
(2) According to a second feature of the present invention that includes the first feature (1), the mounting apparatus further comprises a nozzle-exchanging-device control device which controls, when the nozzle-defect detecting device detects the defective suction nozzle, the nozzle exchanging device to exchange the defective suction nozzle with the normal suction nozzle, while suspending an electric-component mounting operation which is continuously performed when the nozzle-defect detecting device does not detect the defective suction nozzle. The electric-component (xe2x80x9cECxe2x80x9d) mounting operation means, for example, mounting a plurality of ECs on a single circuit substrate (xe2x80x9cCSxe2x80x9d), mounting a single EC on each of a plurality of CSs, or mounting a plurality of ECs on each of a plurality of CSs. In the case where the present EC mounting apparatus is one which can mount ECs in each of a plurality of different mounting manners, the EC mounting operation means mounting ECs in each of the different mounting manners. For example, as will be explained in DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS, in the case where two EC mounting apparatuses take ECs from respective exclusive EC supplying devices, and cooperate with each other to produce an electric circuit by alternately mounting the ECs on a CS, an EC mounting system including the two EC mounting apparatuses may be used in a first mounting manner in which the two EC supplying devices are used to mount ECs on a certain single sort of CSs and include same sorts of EC-supply feeders and all the EC-supply feeders of the two supplying devices are used to mount ECs on each of a plurality of CSs of the single sort. Alternatively, the EC mounting system including the two mounting apparatuses may be used in a second mounting manner in which each of the two EC supplying devices include EC-supply feeders needed to mount ECs on two sorts of CSs and the EC-supply feeders of the two supplying devices are used to mount continuously ECs on each of a plurality of CSs of the two sorts without needing any exchanges of the EC-supply feeders. The EC mounting operation includes all steps that are carried out, for mounting ECs, by the EC mounting apparatuses from the start to the end. Thus, the EC mounting operation includes, in addition to the step of mounting ECs on a CS, the step of sucking and holding the ECs, the step of moving the suction nozzles between the EC supplying devices and the CS, and may additionally include a waiting step in which the EC mounting apparatuses just wait without doing anything. Thus, the nozzle exchange may be performed in the EC mounting operation, for example, in the EC-mounting step, the EC-sucking-and-holding step, the nozzle-moving step, or the waiting step. If the nozzle exchange is performed in the EC-mounting step, the EC-sucking-and-holding step, or the nozzle-moving step, each step is temporarily suspended, and after the exchange, it is resumed. In the waiting step, the nozzle exchange can be performed without suspending any of the above-indicated steps. Since the defective suction nozzle is exchanged with the normal suction nozzle in the EC mounting operation, the present EC mounting apparatus can continue to mount the ECs on the CS with the normal suction nozzle. This contributes to lowering the decrease of the EC mounting efficiency. For example, in the case where the present EC mounting apparatus includes a plurality of suction nozzles and does not use one or more defective suction nozzles to mount ECs on a CS, the number of the suction nozzles that can be used to mount the ECs is decreased by the number of the defective suction nozzles, which leads to lowering the EC mounting efficiency. However, after the defective nozzle or nozzles is/are exchanged with the normal nozzle or nozzles, the present apparatus can mount the ECs on the CS with the pre-programmed (i.e., maximum) number of nozzles. In the case where the present apparatus includes only a single suction nozzle, an EC mounting operation is suspended if the suction nozzle becomes defective. However, since the present apparatus can quickly exchange the defective nozzle with a normal one, it can minimize the suspension time and accordingly the decrease of the EC mounting efficiency. In the case where the EC mounting operation includes a time duration in which the EC mounting apparatus does not mount any ECs, it is preferred that the defective nozzle be exchanged with a normal nozzle in that time duration, because the EC-mounting step need not be suspended for the nozzle exchange. For example, in the case where the present apparatus is designed to mount ECs successively on each of a plurality of CSs, and does not mount any ECs in a time duration after it has mounted all ECs on one CS and before the one CS is replaced with the next CS, the defective nozzle may be exchanged with a normal one in that time duration. Otherwise, when the current sort of CSs on which ECs are currently mounted are changed to another sort of CSs and, in an adjustment time duration, various devices of the present EC mounting apparatus are adjusted to correspond to the new sort of CSs, for example, the CS-position-and-support width of a CS positioning and supporting device for positioning and supporting each CS is adjusted to correspond to the width of the new sort of CSs, the defective nozzle may be exchanged with a normal one in the adjustment time duration. In the case where a plurality of ECs are mounted on a single CS, for example, two EC mounting heads alternately mount ECs on a CS as will be described in DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS, one of the two mounting heads may take a longer time to mount ECs on a CS than a time taken by the other mounting head to take ECs from a corresponding EC supplying device. In this case, while the other mounting head is taking ECs from the corresponding EC supplying device, the defective nozzle of the one mounting head may be exchanged with a normal one by using a time difference of the above-indicated longer and shorter times. In the last case, too, the decrease of the EC mounting efficiency can be minimized.
(3) According to a third feature of the present invention that includes the second feature (2), the mounting apparatus is for mounting a plurality of electric components on the circuit substrate, and the nozzle-exchanging-device control device controls the nozzle exchanging device to exchange the defective suction nozzle with the normal suction nozzle, while suspending the electric-component mounting operation in which the electric components are mounted on the circuit substrate. Alternatively, the defective suction nozzle may be exchanged with the normal suction nozzle, after all the ECs have been mounted on the CS. However, the present apparatus exchanges the defective nozzle with the normal nozzle, while suspending the EC mounting operation. After the exchange, the present apparatus can mount ECs without the defective nozzle, which contributes to minimizing the decrease of the EC mounting efficiency.
(4) According to a fourth feature of the present invention that includes the first feature (1), the mounting apparatus is for mounting a plurality of electric components on the circuit substrate, and at least one of the nozzle-defect detecting device and the nozzle exchanging device is operated in the electric-component mounting operation in which the electric, components are mounted on the circuit substrate. In the case where both of the nozzle-defect detecting device and the nozzle exchanging device are operated in the EC mounting operation, the present EC mounting apparatus can mount, after the nozzle exchange, ECs on a CS without the defective nozzle, which leads to minimizing the decrease of the EC mounting efficiency. In the case where only the nozzle-defect detecting device is operated in the EC mounting operation, the present apparatus can perform the nozzle exchange immediately after the EC mounting operation. And, in the case where only the nozzle exchanging device is operated in the EC mounting operation, the present apparatus can mount, after the nozzle exchange, ECs on a CS without lowering the EC mounting efficiency.
(5) According to a fifth feature of the present invention that includes any one of the first to fourth features (1) to (4), the mounting apparatus further comprises a judging device which judges, when the nozzle-defecting device detects the defective suction nozzle, whether it is needed to exchange the defective suction nozzle with the normal suction nozzle to prevent the defective suction nozzle from holding, by suction, any other electric component. Depending upon, e,g., different sorts and/or degrees of defects, it may, or may not, be needed to exchange the defective suction nozzle with a normal one so as to prevent the defective nozzle from holding any other or additional EC. For example, in the case where the suction nozzle is broken, it is needed to exchange the defect suction nozzle immediately; and in the case where the suction nozzle is curved, stained, or worn, it is not needed to exchange the defect suction nozzle immediately, if the amount of curving, staining, or wearing of the nozzle is too small to affect adversely the EC mounting function of the nozzle. Thus, the judging device judges whether there is a need to exchange the defective nozzle immediately. If not, the nozzle exchanging device may not exchange the defective nozzle with a normal one immediately. In the last case, one or more useless nozzle exchanges can be avoided, which leads to avoiding the decrease of the EC mounting efficiency. In addition, since the time period in which the suction nozzle is used is more or less increased, the running cost of the present apparatus is decreased as such.
(6) According to a sixth feature of the present invention that includes any one of the first to fifth features (1) to (5), the mounting apparatus further comprises a movable member which supports a plurality of suction nozzles which hold, by suction, respective electric components, so that when the movable member is moved, the electric components held by the suction nozzles are simultaneously transferred with the movable member. The movable member may be provided in one of various forms. For example, the movable member may be one which is movable in at least one of two directions which are perpendicular to each other on a reference plane. The movable member may be movable along a straight line, a curved line, or a combination thereof. The plurality of suction nozzles may be directly supported by the movable member, or may be indirectly supported by the movable member via a rotatable body according to the seventh feature (7) that will be described below. Since the movable member simultaneously transfers the plurality of electric components, the movable member is moved between the CS and the EC supplying device less frequently than the case where the movable member supports only one suction nozzle and fetches only one EC from the EC supplying device to mount the one EC on the CS at each time. Thus, this feature contributes to improving the EC mounting efficiency. When one of the plurality of suction nozzles supported by the movable member becomes defective, the present EC mounting apparatus need not immediately exchange the defective nozzle with a normal one. However, if the defective nozzle is exchanged quickly, the total number of movements of the movable member needed to mount all ECs on each CS can be decreased, which leads to minimizing the decrease of the EC mounting efficiency caused by the occurrence of the defective nozzle.
(7) According to a seventh feature of the present invention that includes the sixth feature (6), the movable member comprises a rotatable member which is rotatable about an axis line and which supports the suction nozzles around the axis line, and the rotatable member is moved, and then is rotated to sequentially position each of the suction nozzles at a component-mount position where the each suction nozzle mounts, on the circuit substrate, the electric component held thereby. The axis line may be perpendicular to, parallel to, or inclined relative to, an EC-transfer plane including an EC-transfer route along which the movable member is moved. The rotatable body may be an intermittent-rotation body which is intermittently rotatable in one direction; an intermittent-rotation body which is intermittently rotatable in each of opposite directions; or a rotatably body which is rotatable by an arbitrary angle in an arbitrary direction. The component-mount position may coincide with a component-suck position where each suction nozzle sucks and holds an EC supplied by the EC supplying device, or may differ from the component-suck position.
(8) According to an eighth feature of the present invention that includes any one of the first to seventh features (1) to (7), the nozzle-defect detecting device comprises an image taking device which takes an image of at least a portion of the suction nozzle; and an image processing device which processes image data representing the image taken by the image taking device, and judges whether the suction nozzle has the defect. The image taking device may be one which takes an image of a suction surface defined by a free end surface of the suction nozzle, while facing the suction surface in a direction substantially parallel to an axis line of the nozzle, or one which takes an image of the entire nozzle while facing the nozzle in a direction intersecting the axis line thereof. The image taking device may be provided by a surface-image taking device which can take a surface image of the suction nozzle at once, or by a so-called xe2x80x9cline sensorxe2x80x9d. The surface-image taking device may include a matrix of CCDs (charge-coupled devices) as image taking elements that cooperate with one another to define an image-take surface on which an image is formed. The line sensor may an array of CCDs as image taking elements. In the case where the surface-image taking device takes an image of, e.g., the suction surface defined by the free end surface of the suction nozzle, the image processing device can recognize curving, breaking, wearing, etc. of the suction nozzle. In the case where the line sensor takes an image of the suction nozzle while facing the nozzle in a direction intersecting an axis line thereof, the image processing device can recognize curving or breaking of the nozzle.
(9) According to a ninth feature of the present invention that includes the eighth feature (8), the nozzle-defect detecting device further comprises a defect-detect moving device which moves at least one of the suction nozzle and the image taking device relative to the other of the suction nozzle and the image taking device. The defect-detect moving device moves the suction nozzle and the image taking device relative to each other, for the purpose of detecting a defect of the suction nozzle, or positioning the suction nozzle at an image-take position. For example, in the case where the line sensor is employed as the image taking device, the image processing device can obtain a two-dimensional image of the nozzle by moving the nozzle and the line sensor relative to each other, and can recognize how the nozzle as a whole is curved.
(10) According to a tenth feature of the present invention that includes any one of the first to ninth features (1) to (9), the nozzle-defect detecting device comprises a beam emitting device which emits a light beam in a direction intersecting an axis line of the suction nozzle; and a beam detecting device which detects the light beam which has been emitted by the beam emitting device and has been affected by the suction nozzle. The light beam may be a common light having a wide spectrum. However, in the case where the light beam is a laser beam, the nozzle-defect detecting device can improve its resolution. In the case where the beam emitting device is provided by an LED (light emitting diode), the LED emits, as the light beam, a multi-color light having a wide spectrum. In the case where the beam emitting device is provided by a laser-beam emitting device, the laser beam is a mono-color light having a narrow spectrum. The light beam affected by the suction nozzle may be a light beam reflected by the nozzle, or a light beam which has passed around the nozzle. The beam emitting and detecting devices may be provided by a transmission-type or reflection-type photoelectric sensor that includes a light source, a light emitter, and a light receiver including a light detecting element. In the case of the transmission-type photoelectric sensor, the light receiver receives, as the light beam affected by the suction nozzle, the light beam which has passed around the nozzle. In the case of the reflection-type photoelectric sensor, the light receiver receives, as the light beam affected by the suction nozzle, the light beam which has been reflected by the nozzle.
(11) According to an eleventh feature of the present invention that includes the tenth feature (10), the nozzle-defect detecting device further comprises a defect-detect moving device which moves at least one of the suction nozzle and a combination of the beam emitting device and the beam detecting device to the other of the suction nozzle and the combination. The defect-detect moving device moves the suction nozzle and the beam emitting and detecting devices relative to each other, for the purpose of detecting a defect of the suction nozzle, or positioning the suction nozzle at an image-take position. In the case where the nozzle and the beam emitting and detecting devices are moved, for detecting a defect of the nozzle, relative to each other, e.g., in a direction having a component intersecting an axis line of the nozzle, the nozzle-defect detecting device can detect curving of the nozzle irrespective of whichever diameter the nozzle may have, because the curved nozzle affects the light beam at a timing different than that at which a normal nozzle does.
(12) According to a twelfth feature of the present invention that includes the ninth or eleventh feature (9) or (11), the defect-detect moving device comprises a nozzle moving device which moves the suction nozzle in a direction having at least one of a first direction component intersecting an axis line of the suction nozzle and a second direction component parallel to the axis line. As described above in connection with the eleventh feature (11), if the suction nozzle is moved in a direction having a component intersecting the axis line of the nozzle, the nozzle-defect detecting device can detect curving of the nozzle irrespective of the diameter of the nozzle. Likewise, if the suction nozzle is moved in a direction having a component parallel to the axis line of the nozzle, the nozzle-defect detecting device can detect curving or breaking of the nozzle, based on a timing at which the light beam is affected by the nozzle. At least a portion of the defect-detect moving device of a type that moves the suction nozzle in a direction having a component intersecting the axis line of the nozzle, may be commonly shared by an EC-transfer moving device which moves the nozzle to transfer the EC held thereby, or may be provided by an exclusive or independent moving device. As will be explained in DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS, the section nozzle may be elevated and lowered, for mounting the EC on the CS, by an elevating and lowering device in a direction parallel to the axis line of the nozzle. In this case, the defect-detect moving device may be provided by the elevating and lowering device.
(13) According to a thirteenth feature of the present invention that includes any one of the ninth, eleventh, and twelfth features (9), (11), and (12), the defect-detect moving device comprises a nozzle rotating device which rotates the suction nozzle about an axis line thereof. Since the suction nozzle is rotated, the nozzle can be viewed in a plurality of directions on a reference plane intersecting the axis line of the nozzle, so that a defect of the nozzle can be detected with reliability. For example, if the nozzle is curved in a direction parallel to a direction in which the light beam is emitted and the curved nozzle is located on a plane including the path of travelling of the beam, it is difficult to judge whether the nozzle is curved or not. However, when the curved nozzle is rotated, the nozzle will be deviated from that plane at some angular phase, so that the curving of the nozzle can be detected. As will be described in DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS, the present EC mounting apparatus may employ a nozzle rotating device which rotates a suction nozzle about its axis line to change the current rotation position of an EC held thereby, and/or correct a rotation-position error of the EC. In this case, the thus employed nozzle rotating device may provide the nozzle rotating device of the defect-detect moving device. In the last case, the nozzle-defect detecting device may detect a defect of the nozzle, either while the nozzle is rotated to change the current rotation position of the EC and/or correct the rotation-position error of the EC, or while the nozzle is rotated for this particular purpose independent of changing of the current rotation position of the EC and/or correcting of the rotation-position error of the EC.
(14) According to a fourteenth feature of the present invention that includes any one of the first to thirteenth features (1) to (13), the nozzle-defect detecting device comprises a failure detecting device which detects a failure of the suction nozzle to hold, by suction, an electric component; and a judging device which judges, based on the detected failure, whether the suction nozzle has the defect. If the suction nozzle has a defect, the nozzle may fail to hold an EC, for example, it does not hold an EC when it should do, or it holds an EC which, however, has an inappropriate posture in which the EC cannot be mounted. Thus, a defect of the nozzle can be detected by detecting a failure of the nozzle to hold an EC. A failure of the nozzle to hold an EC can be detected in various manners. For example, if the nozzle fails to hold an EC when it should do, a much more amount of air flows into the nozzle without the EC than the amount of air that would flow into the nozzle with the EC. Therefore, upon occurrence of a failure, for example, a negative pressure in a suction passage of the nozzle is weakened, or a vacuum pump is operated at an increased speed to maintain the negative pressure of the suction passage at a predetermined value. Thus, the failure detecting device can detect the failure. Otherwise, the failure detecting device may employ an image taking device which takes an image of an EC held by the nozzle. In this case, the failure detecting device can detect a failure of the nozzle based on the taken image. As will be described in DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS, the present EC mounting apparatus may employ an image taking device which takes an image of an EC held by a suction nozzle, for the purpose of mounting the EC in an appropriate posture on a CS. In this case, the thus employed image taking device may provide the image taking device of the failure detecting device. Alternatively, the failure detecting device may employ an image taking device which is exclusively used to detect a failure of the nozzle to hold an EC.
(15) According to a fifteenth feature of the present invention that includes the fourteenth feature (14), the judging device comprises a static-analysis device which statistically analyzes a plurality of failures detected by the failure detecting device, and judges, based on the static analysis of the static-analysis device, whether the suction nozzle has the defect. The present failure detecting device detects a plurality of failures of the suction nozzle to hold a plurality of ECs, the static-analysis device statistically analyzes the detected failures, and the judging device judges, based on the static analysis of the static-analysis device, whether the suction nozzle has a defect. Thus, the judging device can make a positive or negative judgement with high reliability.
(16) According to a sixteenth feature of the present invention that includes any one of the first to fifteenth features (1) to (15), the nozzle exchanging device comprises a nozzle storing device which stores a plurality of suction nozzles such that each one of the suction nozzles is removable therefrom independent of the other suction nozzles; and a nozzle-exchange moving device which performs a nozzle-exchange movement including a combination of a first relative movement of the each suction nozzle and the nozzle storing device in a direction parallel to an axis line of the each suction nozzle and a second relative movement of the each suction nozzle and the nozzle storing device in a direction perpendicular to the axis line. It is preferred that at least a portion of the nozzle-exchange moving device be commonly shared by the defect-detect moving device according to the twelfth feature (12). Alternatively, at least a portion of the nozzle-exchange moving device be commonly shared by an EC-transfer moving device which moves the suction nozzle to transfer the EC held by the nozzle. It is possible that the nozzle-exchange moving device, the defect-detect moving device, and the EC-transfer moving device share at least a portion thereof. In the last case, the EC mounting apparatus can enjoy a simple construction.
(17) According to a seventeenth feature of the present invention that includes the sixteenth feature (16), the nozzle exchanging device further comprises a nozzle holder which holds the suction nozzle in a state in which the nozzle holder permits the suction nozzle to be removed therefrom when being drawn with a force having a direction toward a free end thereof and a magnitude greater than a reference value; and a permitting and inhibiting device which is supported by the nozzle storing device and which is selectively placed in a permitting state in which the permitting and inhibiting device permits the suction nozzle held by the nozzle holder to be stored by the nozzle storing device by being moved in one of opposite directions parallel to an axis line of the suction nozzle and permits each of the suction nozzles stored by the nozzle storing device to be removed from the nozzle storing device by being moved in the other direction, and an inhibiting state in which the permitting and inhibiting device inhibits the suction nozzle held by the nozzle holder from being stored by the nozzle storing device by being moved in the one direction and inhibits the each suction nozzle stored by the nozzle storing device from being removed from the nozzle storing device by being moved in the other direction. In the state in which the permitting and inhibiting device is placed in the inhibiting state, each suction nozzle is inhibited from being removed from the nozzle storing device; but in the state in which the permitting and inhibiting device is placed in the permitting state, each suction nozzle can be easily removed from the nozzle storing device. When the suction nozzle held by the nozzle holder is drawn with a force having a magnitude greater than a reference value in a direction parallel to the axis line of the nozzle, the nozzle can be easily removed from the holder.
(18) According to an eighteenth feature of the present invention that includes the seventeenth feature (17), each of the suction nozzle held by the nozzle holder and the suction nozzles stored by the nozzle storing device includes a holdable portion which can be held by the nozzle holder, and a shoulder surface facing toward a side of the holdable portion, and the nozzle storing device comprises a nozzle storing member, a nozzle-removal inhibiting member, and a nozzle-removal-inhibiting-member moving device, the nozzle storing member having a plurality of nozzle storing holes which are formed along a reference plane and each of which can accommodate a free-end-side portion of the each suction nozzle that is located between a free end thereof and the shoulder surface thereof, the nozzle-removal inhibiting member being movable along the reference plane, and having a plurality of through-holes which correspond to the plurality of nozzle storing holes of the nozzle storing member, respectively, and each of which permits the free-end-side portion of the each suction nozzle to be passed therethrough in the opposite directions parallel to the axis line of the each suction nozzle, and a plurality of nozzle-removal inhibiting portions which are adjacent to the plurality of through-holes, respectively, and each of which can engage the shoulder surface of the each suction nozzle to prevent the each suction nozzle from being removed from the nozzle storing member, the nozzle-removal-inhibiting-member moving device moving the nozzle-removal inhibiting member to an operative position thereof where each of the nozzle-removal inhibiting portions can engage the shoulder surface of the each suction nozzle and to an inoperative position thereof where the plurality of through-holes are aligned with the plurality of nozzle storing holes, respectively, the permitting and inhibiting device comprising the nozzle-removal inhibiting member and the nozzle-removal-inhibiting-member moving device. When the suction nozzle held by the nozzle holder is returned to the nozzle storing member, the nozzle-removal inhibiting member is moved to the inoperative position where the inhibiting member permits the nozzle holder to return the suction nozzle held thereby, to the nozzle storing member and permits the nozzle held by the nozzle holder to be held by the storing member as well. Subsequently, the inhibiting member is moved to the operative position where the inhibiting member inhibits the nozzle held by the nozzle holder and the storing member, from being removed from the storing member. Then, when the nozzle holder is moved in a direction away from the storing member, the nozzle is drawn with a force greater than a reference value in a direction in which the nozzle is removed from the holder, so that the nozzle is removed from the holder.
(19) According to a nineteenth feature of the present invention, there is provided an apparatus for performing a series of electric-component mounting operations, the apparatus comprising a mounting device which mounts, according to a prescribed electric-component mounting program, a plurality of electric components on each of a plurality of circuit substrates in a corresponding one of the series of electric-component mounting operations; and an in-operation nozzle exchanging device which exchanges a defective suction nozzle with a normal suction nozzle in the series of electric-component mounting operations. Since the defective suction nozzle is exchanged with a normal one in the series of EC mounting operations, the present apparatus can continue, without the defective nozzle, the series of EC mounting operations after the nozzle exchange till the end of the last one of the series of EC mounting operations. Therefore, the degree of lowering of the EC mounting efficiency can be decreased as compared with the case where the nozzle exchange is carried out after the end of the series of EC mounting operations.
(20) According to a twentieth feature of the present invention that includes the nineteenth feature (19), the in-operation nozzle exchanging device exchanges the defective suction nozzle with the normal suction nozzle in the one of the series of electric-component mounting operations in which the mounting device mounts the plurality of electric components on the each circuit substrate. The present apparatus can enjoy the same advantages as those of the EC mounting apparatus according to the third feature (3).
(21) According to a twenty-first feature of the present invention, there is provided a method of moving at least one suction nozzle holding, by suction, an electric component, and mounting, on a circuit substrate, the component held by the nozzle, the method comprising the steps of detecting a defect of the suction nozzle, and automatically exchanging the defective suction nozzle having the detected defect, with a normal suction nozzle. The present method can enjoy the same advantages as those of the EC mounting apparatus according to the first feature (1).
(22) According to a twenty-second feature of the present invention, there is provided a method of performing a series of electric-component mounting operations in each of which a plurality of electric components are mounted, according to a prescribed electric-component mounting program, on a corresponding one of a plurality of circuit substrates, the method comprising the step of exchanging a defective suction nozzle with a normal suction nozzle in the series of electric-component mounting operations. The present method can enjoy the same advantages as those of the EC mounting apparatus according to the second feature (2).
(23) According to a twenty-third feature of the present invention that includes the twenty-second feature (22), the step of exchanging the defective suction nozzle with the normal suction nozzle comprises exchanging the defective suction nozzle with the normal suction nozzle in the each of the series of electric-component mounting operations in which the plurality of electric components are mounted on the one circuit substrate. The present method can enjoy the same advantages as those of the EC mounting apparatus according to the third feature (3).
(24) According to a twenty-fourth feature of the present invention that includes the twenty-second or twenty-third feature (22) or (23), the mounting method further comprises detecting, in the series of electric-component mounting operations, a defect of a suction nozzle, and the step of exchanging the defective suction nozzle with the normal suction nozzle comprises exchanging the defective suction nozzle having the detected defect, with the normal suction nozzle, to prevent the defective suction nozzle from holding, by suction, any other electric component.
(25) According to a twenty-fifth feature of the present invention that includes the twenty-second or twenty-third feature (22) or (23), the mounting method further comprises detecting, in the series of electric-component mounting operations, a defect of a suction nozzle, and continuing the series of electric-component mounting operations without instantly exchanging the defective suction nozzle having the detected defect, with the normal suction nozzle, and the step of exchanging the defective suction nozzle with the normal suction nozzle comprises exchanging, when a predetermined condition is satisfied, the defective suction nozzle having the detected defect, with the normal suction nozzle. The predetermined condition is, for example, that an amount of curving of the suction nozzle is too great to use the nozzle for mounting ECs on a CS; that all ECs have been mounted on one CS; that the series of EC mounting operations has ended; that in the case where a plurality of suction nozzles are employed, a defect of each of the nozzles has been detected; or that in the case where the series of EC mounting operations includes a waiting step in which the suction nozzle waits for mounting ECs, the waiting step has started. In the present EC mounting method, since a timing at which the defective nozzle is exchanged with a normal one is delayed from a timing at which the defective nozzle is detected, the period of use of the nozzle is increased, which leads to reducing the increase of the cost of nozzles. In addition, in the case where the defective nozzle is exchanged with a normal one in the waiting step in which the nozzle is not used for mounting ECs on a CS, the decrease of the EC mounting efficiency is reduced.
Each of the twenty-first to twenty-fifth features (21) to (25) of the EC mounting method according to the present invention may be combined with any one of the first to twentieth features (1) to (20) of the EC mounting apparatus according to the present invention.